Back in the mid-90s, as the general public started to get accustomed to this new way of talking to people in other parts of the globe using computers, a few discovered internet discussion groups. A standard 'me too' thread would look like this:

Me too threads could grow to over a hundred responses, and consisted almost exclusively of AOL members. AOL seemed to have cornered the market on idiots at the time. Other newsgroup readers dispised me too threads, because they wasted bandwidth, and sometimes caused more legitimate messages to be dropped from those early-version servers prematurely.

Question:So why didn't dumbass@aol.com just post the information straight to the group?
Answer:I don't know, but I can speculate:

dumbass didn't know how to post attachments to a newsgroup on AOL. At first I thought this was the most likely answer, but then I asked myself: he can put attachments on his email...why not put it on a post?

AOL didn't allow attachments beyond a certain size to be posted to newsgroups. This makes more sense. By allowing a 1-meg file to be posted to a newsgroup, AOL risks having thousands of its members try to download it through its pipes. By allowing large attachments on email only, AOL could cut bandwidth this way. I don't know if this is true or not, because I have never been signed up with AOL.

dumbass didn't want to break the rules of the newsgroup. Almost as annoying as the new "me too"ers from AOL were the defensive old farts from CompuServe or university accounts that put out puling complaints whenever a binary was posted in a non-binary group. Some of these groups were moderated, and dumbass didn't want to take chances.

"dumbass@aol.com" was an entity collecting email addresses. By asking people to post their emails, the original poster was effectively harvesting good email addresses from people that would otherwise not post in a newsgroup. These email addresses would then be fed to spambots to give the unwitting repliers the punishment they so richly deserved.

It may have also been, in the case where "dumbass@aol.com" was offering kiddie porn or rape footage, that the feds were running a kind of trolling operation to collect email addresses of possible sex offenders.

Today, me too threads seem to have dissappeared from usenet. A search for "me too" on deja news brings up no such threads in the 100 most recent hits. I have some speculation on the cause of this as well:

"Me too" is also the name of an advertising technique where the ad displays attractive and desirable scenes, and implies that whoever is watching the ad will also achieve such pleasant results if s/he uses the product being advertised.

A typical example is a Claritin commercial. You see some people, with their family, running around in a big, pure green field, and a pure blue sky, having fun, smiling, and flying kites. Looks good? Especially to people with allergies? You bet. They say "Me too!" and they run out and buy Claritin so that they too, can experience this wonderful scene.

Ok, so it's not QUITE like that, but that's what this technique's basic theory is. Soda commercials do this a lot too. Remember the people all dancing and having fun in those Dr. Pepper ads? Or the Life Tastes GoodCoke ads? You see these all over the place. Not just on TV, either. Beer and cigarette ads tend to favor this style in print publications too. I'm not entirely sure, but I think it might be the most common format for advertisements, all in total.